New estimates of the distances of 36 nearby galaxies are presented based on accurate distances of galactic Cepheids obtained by Gieren et al. (1998ApJ...496...17G) from the geometrical Barnes-Evans method. The concept of ``sosie'' is applied to extend the distance determination to extragalactic Cepheids without assuming the linearity of the PL relation. Doing so, the distance moduli are obtained in a straightforward way. The correction for extinction is made using two photometric bands (V and I) according to the principles introduced by Freedman & Madore (1990ApJ...365..186F).
We present the results of a detailed multiphase spectroscopic analysis of six classical Cepheids with pulsation periods between 3 and 6 days. For each star we have derived phased values of effective temperature, surface gravity, microturbulent velocity, and elemental abundances. We show that the elemental abundance results for these Cepheids are consistent for all pulsational phases.
Cepheus A SFR XMM-Newton X-Ray Point Source Catalog
Short Name:
CEPAXMM
Date:
27 Sep 2024
Publisher:
NASA/GSFC HEASARC
Description:
Cepheus A is a star formation region (SFR) at a distance of ~ 730 pc consisting of two main H II regions, Cep A East and Cep A West. Cep A was observed with the EPIC cameras of the XMM-Newton observatory on 2003 August 23 for 43.9ks. In this observation, X-rays from both components of Cep A, East and West, were discovered by XMM-Newton, as well as from the Herbig-Haro object HH 168, which joins the ranks of other energetic H-H objects that are sources of temperature T >= 10<sup>6</sup> K X-ray emission. A total of 102 distinct X-ray sources were detected in this 44 ks observation, many presumed to be pre-main-sequence stars on the basis of the reddening of their optical and IR counterparts, the latter being found by matching the positions of the 102 X-ray sources with objects in the USNO-B1.0 (Monet et al. 2003, AJ, 125, 984) and Two Micron All Sky Survey (2MASS) catalogs using a 2.5" matching radius. The authors performed source detection on all the XMM-Newton data in two energy bands: 0.2 - 1 keV ("soft") and 1 - 10 keV ("hard"). They detected 24 soft sources and 85 hard sources. Seven of the sources appear in both bands, where the criterion for a match between the bands is a positional offset of < 2.5 arcseconds. Thus, the total number of distinct X-ray sources detected (and listed in this table) is 102. This table was created by the HEASARC in July 2007 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/626/272">CDS Catalog J/ApJ/626/272</a> file table2.dat. This is a service provided by NASA HEASARC .
Protostellar jets and outflows are key features of the star-formation process, and primary processes of the feedback of young stars on the interstellar medium. Understanding the underlying shocks is necessary to explain how jet and outflow systems are launched, and to quantify their chemical and energetic impacts on the surrounding medium. We performed a high-spectral resolution study of the [OI]63um emission in the outflow of the intermediate-mass Class 0 protostar Cep E-mm. The goal is to determine the structure of the outflow, to constrain the chemical conditions in the various components, and to understand the nature of the underlying shocks, thus probing the origin of the mass-loss phenomenon. We present observations of the OI ^3^P_1_ -> ^3^P_2_, OH between ^2^{Pi}_1/2_ J=3/2 and J=1/2 at 1837.8GHz, and CO (16-15) lines with the GREAT receiver onboard SOFIA towards three positions in the Cep E protostellar outflow: Cep E-mm (the driving protostar), Cep E-BI (in the southern lobe), and Cep E-BII (the terminal position in the southern lobe).
Results of an objective prism Schmidt survey are combined with IRAS survey data in order to assess the star-forming activity in the Cepheus Flare, a nearby giant molecular cloud complex at ~15{deg} above the Galactic equator. The distribution of absorbing matter along the line of sight was also studied. The Wolf diagrams, displaying the cumulative distribution of field star distance moduli, show that the interstellar matter in this region is concentrated at three characteristic distances: 200, 300, and 450pc. The three components, though partly overlapping, can be separated along the Galactic latitude. Within the area of the Cepheus Flare, distances are determined for 14 Lynds dark clouds and for some other clouds.
The CepOB2 region, with its two intermediate-aged clusters Tr37 and NGC7160, is a paradigm of sequential star formation and an ideal site for studies of protoplanetary disk evolution. We use Herschel data to study the protoplanetary disks and the star formation history of the region. Herschel/PACS observations at 70 and 160{mu}m probe the disk properties (mass, dust sizes, structure) and the evolutionary state of a large number of young stars. Far-IR data also trace the remnant cloud material and small-scale cloud structure. We detect 95 protoplanetary disks at 70{mu}m, 41 at 160{mu}m, and obtain upper limits for more than 130 objects. The detection fraction at 70{mu}m depends on the spectral type (88% for K4 or earlier stars, 17% for M3 or later stars) and on the disk type (~50% for full and pre-transitional disks, ~35% for transitional disks, no low-excess/depleted disks detected). Non-accreting disks are not detected, suggesting significantly lower masses. Accreting transition and pre-transition disks have systematically higher 70{mu}m excesses than full disks, suggestive of more massive, flared and/or thicker disks. Herschel data also reveal several mini-clusters in Tr37, which are small, compact structures containing a few young stars surrounded by nebulosity. Far-IR data are an excellent probe of the evolution of disks that are too faint for sub-millimetre observations. We find a strong link between far-IR emission and accretion, and between the inner and outer disk structure. Herschel confirms the dichotomy between accreting and non-accreting transition disks. Accretion is a powerful measure of global disk evolution: substantial mass depletion and global evolution need to occur to shut down accretion in a protoplanetary disk, even if the disk has inner holes. Disks likely follow different evolutionary paths: low disk masses do not imply opening inner holes, and having inner holes does not require low disk masses. The mini-clusters reveal multi-episodic star formation in Tr37. The long survival of mini-clusters suggest that they formed from the fragmentation of the same core. Their various morphologies favour different formation/triggering mechanisms acting within the same cluster. The beads-on-a-string structure in one mini-cluster is consistent with gravitational fragmentation or gravitational focusing, acting on very small scales (solar-mass stars in ~0.5pc filaments). Multi-episodic star formation could also produce evolutionary variations between disks in the same region. Finally, Herschel also unveils what could be the first heavy mass loss episode of the O6.5 star HD 206267 in Tr 37.
VLA observations at 4.9GHz are given for 144 steep-spectrum 4C sources whose declinations are between -4{deg} and +4{deg} and whose angular sizes are smaller than 30arcsec. The paper contains 150 maps (VLA and 6 MERLIN observations at 1420 or 1658MHz) which are not included here.
We present a spectroscopic survey of a sample of F stars that have not yet been searched for planets. The observations of 187 stars obtained with the Bochum Echelle Spectrographic Observer of the Cerro Armazones Observatory were aimed at nearby (closer than 70pc) main-sequence stars without sufficient archive ([fiber-fed extended range optical spectrograph (FEROS)/high accuracy radial velocity planet search (HARPS)]) spectroscopy. The primary goal of the survey was to select the best candidates for radial-velocity searches of extrasolar planets. The spectra were analysed using the broadening-function technique, the method of choice for rapid rotators later than about A5. The analysis was focused not only at the determination of projected rotational velocity (defining precision of radial-velocity determination), but also at the detection of previously unknown spectroscopic binaries/multiples or stars showing strong line asymmetries. 12 previously unknown spectroscopic binaries/triples were detected. For all observed targets the spectral type was determined. About 140 stars are rotating faster than the resolution limit of 10km/s sampling the onset of convection and slow rotation at mid-F spectral types in great detail. Radial-velocity precision of the data (about 100m/s) is insufficient to detect planets but could indicate most SB1 systems with stellar companions. As there are already 2-3 observations per object for these newly detected binary stars, only a few additional follow-up observations will be needed to obtain constraints on orbital parameters. We identified a sample of 68 bright F-type dwarf stars which are perfect targets for future planet searches. They rotate moderately or slowly and do not show any sign of binarity, pulsations, or surface activity.
The CeSAM Virtual Observatory Server's TAP end point. The Table Access
Protocol (TAP) lets you execute queries against our database tables,
inspect various metadata, and upload your own data. It is thus the
VO's premier way to access public data holdings.
Tables exposed through this endpoint include: main from the aspic_6df schema, g02, g09g12g15 from the aspic_gama schema, main from the aspic_muse_wide schema, w1, w1_video, w4 from the aspic_vipers schema, cosmos, ecdfs from the aspic_vuds schema, catalogue, spectra from the el_cosmos_dr1 schema, spectra from the gama_dr3 schema, obscore from the ivoa schema, spectra from the muse_wide_dr1 schema, bolshoi2022, uchuu2022 from the sides schema, columns, groups, key_columns, keys, schemas, tables from the tap_schema schema, spectra from the vipers_dr2 schema, spectra from the vuds_dr1 schema, spectra from the zcosmos_20k schema.
This paper presents a large sample of intermediate- to high-redshift galaxy groups and clusters detected using a fully automated search in the Cosmic Evolution Survey field. The detection algorithm is based on density peak extraction from a density distribution sampled using Voronoi tessellation within overlapping slices in the photometric redshift space. The cluster catalogue contains 1780 structures covering the redshift range 0.2<z<3.0, spanning three orders of magnitude in luminosity (10^8^<L_4_<5x10^11^L_{sun}_) and richness from eight to hundreds of galaxies. All clusters at z>0.4 and many even below this threshold show very prominent substructure indicating that z~0.4 marks the slow emergence of virialized clusters in this field in agreement with published findings for other regions of the sky. The redshift distribution of detected structures shows strong variations with prominent peaks suggesting the presence of large-scale structures across the whole range covered by this catalogue. Supercluster candidates have been identified at redshifts z=0.35, 0.72, 0.94, 1.12, 1.27, 1.45, 2.0 and 2.52. At z=2.9 we identified a compact agglomeration of galaxy groups and clusters suggesting the presence of another supercluster-like structure which has been the highest redshift candidate so far. Out of the nine supercluster candidates found in this study, six are new detections.